Command line terminals are of current use for controlling the operation of a computer (e.g., controlling the computer's configuration, accessing and controlling a file system, making network connections), of a chemical or manufacturing process, of a piece of equipment (e.g., a network unit), etc.
Command line expansion refers to expanding a command line that is partially typed in with a guess of what the operator is expected to enter next. Command line expansion is supported by most UNIX shell flavours, such as cshell, kshell, bash, etc, as well as by LINUX and Windows® operating systems.
These command expansion algorithms works fine provided the editing cursor is positioned at the end of the command line. Yet, if the operator starts overwriting partially an already typed in command, being in “inserting” mode or in “overwriting mode”, e.g. for substituting a new command word for a former one, and next asks for expansion before the modification is completed, then the expansion does not work or is completely messed up, making such prior art solutions ineffective.
A common workaround is to overwrite the already typed in command until the modification is syntactically coherent, e.g. until the whole new command word is substituted, that is to say without even the need for further command expansion.